764368domain: NAppears in sequencesNumber of permutations of order n avoiding the consecutive pattern 131'2.at n=10A177475G.f.: Sum_{n>=0} x^n / (1-3*x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * 2^k * x^k] * [Sum_{k=0..n} C(n,k)^2 * 3^k * x^k].at n=7A246423